Mesenchymal Stem Cells for the Treatment of Perianal Fistulizing Crohn's Disease

Crohn's disease (CD), a chronic transmural inflammatory disease of the gastrointestinal tract, continues to increase in incidence for unknown reasons. According to population based studies, at least 26% of patients with CD will develop perianal fistulas in the first two decades following diagnosis, particularly those with colonic and rectal involvement. These patients experience significant morbidity due to pain, persistent drainage, recurrent perianal sepsis, and ongoing need to access medical care resulting in increased costs and impaired quality of life. Unfortunately, perianal fistulizing Crohn's disease is notoriously difficult to cure with 37% of patients experiencing refractory disease. As a result, patients cycle through numerous immunosuppressive medications that can have significant side effects, and \>90% undergo multiple surgical interventions putting them at risk of incontinence. The specific rationale for MSCs in perianal Crohn's fistulas is based upon 1) their anti-inflammatory and immunomodulatory properties; 2) several studies reporting the safety and efficacy of MSCs for the treatment of perianal Crohn's fistula; 3) existence of safe manufacturing methods for isolation and expansion of MSCs. This study will enroll 20 participants that have Crohn's disease with medically and surgically refractory perianal fistulizing disease. Participants enrolled will be those that meet particular criteria for participation in the clinical trial. Enrolled participants will be randomized to treatment group with adult allogeneic bone marrow derived mesenchymal stem cells, versus placebo in a 3:1 fashion. Participants in the treatment group will have a direct injection of MSCs at a dose of 75 million cells. This will be given as a direct injection in and around the fistula tract. Participants will be evaluated for complete healing at three months. If complete healing has been achieved, participants will continue to be followed for one year. If complete healing has not been achieved at three months, participants will be eligible for a second injection of MSCs at the same dose of 75 million cells. Control participants without complete healing from placebo will cross over at the 6 month visit to receive an injection of MSCs and again three months after this as above, and will be followed for one year after treatment to a total duration of 18 months.